Evolution of baroclinic planetary eddies over localized bottom topography in terms of JEBAR
Evolution of baroclinic planetary eddies over localized bottom topography in terms of JEBAR
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JEBAR 局部底部地形上斜压行星涡流的演化
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
T. Yamagata
中科院分区：
文献类型：
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作者：
T. Sakamoto;T. Yamagata
本文用两层行星地转方程组研究了有局域海底地形时纯斜压涡旋的演变。特别是，我们用JEBAR(斜压性和起伏的共同作用)来解释涡旋运动。结果表明，涡旋与底地形相互作用时，会产生正压流(或波)的释放、向西加速和能量转换。经向脊线对JEBAR引起的正压气流(或波)产生的冷涡起排斥作用，对暖涡起吸引子作用，这与涡度理论一致。这一机制不仅可以解释TOPEX/POSEIDON卫星高度计在太平洋观测到的斜压Rossby波相速度的全球分布，也可以解释北大西洋观测到的向西传播的斜压涡旋轨迹的突变。
Abstract Numerical experiments have been conducted to investigate the evolution of pure baroclinic eddies using two-layer planetary geostrophic equations in the presence of localized bottom topography. In particular, we interpret the eddy motion in terms of JEBAR (joint effect of baroclinicity and relief). It is shown that the emission of barotropic flows (or waves), westward acceleration and energy conversion occur when an eddy interacts with bottom topography. A meridional ridge acts as a repellor for a cold eddy and an attractor for warm eddy due to JEBAR-induced barotropic flows (or waves), which is consistent with the vorticity argument. This mechanism may provide a possible explanation not only for the global distribution of the phase speed of baroclinic Rossby waves observed in the Pacific by the TOPEX/POSEIDON satellite altimeter but also for the abrupt change in the trajectories of the westward propagating baroclinic eddies observed in the North Atlantic.